Shocks in dense clouds IV. Effects of grain-grain processing on molecular line emission

• Published in: Astronomy and astrophysics (Berlin) Vol. 556; pp. 1 - 26
• Main Authors: Anderl, S, Guillet, V, des Forets, G Pineau, Flower, D R
• Format: Journal Article
• Language: English
• Published: EDP Sciences 01.08.2013
• Subjects: Astrophysics; Emission; Fragmentation; Galactic Astrophysics; Grains; Modelling; Rotational; Sciences of the Universe; Silicon dioxide; Vaporization
• ISSN: 0004-6361; 1432-0746; 1432-0756
• DOI: 10.1051/0004-6361/201321399

Grain-grain processing has been shown to be an indispensable ingredient of shock modelling in high density environments. Shattering is accompanied by the vaporization of grains, which can, in addition to sputtering, directly release SiO to the gas phase. Given that SiO rotational line radiation is used as a major tracer of shocks in dense clouds, it is crucial to understand the influence of vaporization on SiO line emission. We extend our study of the impact of grain-grain processing on C-type shocks in dense clouds. Various values of the magnetic field are explored. We have developed a recipe for implementing the effects of shattering and vaporization into a 2-fluid shock model, resulting in a reduction of computation time by a factor [similar]100 compared to a multi-fluid modelling approach. The release of SiO early in the hot shock changes the excitation characteristics of SiO radiation, although it does not yield an increase in width for the line profiles. To significantly increase the intensity and width of SiO rotational lines, SiO needs to be present in grain mantles.